Direct from manufacturer: Stainless steel or carbon steel environmental zinc plated rivet bolts, stud bolts, hex bolts, rivet screws: BSOS-M3-L, BSOS-M4-L, BSOS-M5-L, BSOS-M6-L, BSOS-M8-L, SOS-M3-L, SOS-M4-L, SOS-M5-L, SOS-M6-L, SOS-M8-L, BSO-M3-L, BSO-M4-L, BSO-M5-L, BSO-M6-L, BSO-M8-L, SO-M3-L, SO-M4-L, SO-M5-L, S